In Indiana Jones and the Temple of Doom (1984), Steven Spielberg happily exploits swinging bridge anxiety. Indy and his companions cross a high Himalayan chasm on an old, ill-repaired bridge that, as the audience well knows, will either collapse or be cut loose, leaving our hero dangling precipitously. Spielberg’s setting is appropriate even if his staging is outlandish. The Himalayas are indeed home to swinging bridges, many in high mountain gorges.
Unlike the Shenandoah Valley where they serve as an emergency substitute for an extant but vulnerable transportation system, Himalayan swinging bridges are often the only way in and out of an area. In those mountains, transportation is difficult and tenuous. Paths are subject to slips. The bridges are constructed from the materials and knowledge available, and maintained by the local population. Even bridges serving the main routes between villages often have treadways with broken, missing, or rotten boards, demanding careful, often hesitant stepping and which may explain why those bridges are often festooned with strings of flapping prayer flags.
Early in the 20th century, James Burtton bought farmland along the Tokumaro River on the North Island of New Zealand. Isolated from transportation routes and therefore unable to bring his farm products to market, he built—by hand—a nearly five kilometer track from his station to the road. His house was also isolated, having been built on the east side of the river while his livestock grazed on the west. Ever the intrepid Kiwi, Burtton constructed a swinging bridge that provided both his livelihood and the cause of his death. In 1941, one of the cables gave way as he crossed the bridge, and he fell to the rocks below, breaking his leg and sustaining other injuries. He spent twelve hours crawling to his neighbor’s house, only to die soon after.
Swinging bridges remain a common feature of the New Zealand landscape, but today most are maintained by the Department of Conservation and built to fairly standard specifications. In additional to suspension cables made of steel, most have three lower cables spaced by metal bars and covered by a layer of chain-link fencing to serve as the treadway. The anxiety these bridges produce arises not from worries about their structural integrity, but instead by virtue of their locations—often set high above rushing waters linking sheer rock faces. Getting on and off of them can be more frightening than crossing. However the narrow treadway does make for lateral swinging which is usually dampened by diagonal cables anchored about a third of the way across.
Still, trust even in this standardized construction technique and maintenance can be misplaced, something learned by four French hikers in September of 2015. A short video made by one while crossing the Hopurahine Bridge on the Lake Waikaremoana Great Walk shows the bridge making a sudden lateral twist, flipping the treadway over to the hikers’ left, pitching them over the right side of the cable railing, and depositing them in the water below. The bridge then snapped back almost as if nothing had happened.
Unlike Burtton, the hikers were unharmed. Of course the Department of Conservation did an immediate study of the cause and inventoried the many bridges in their purview, but that doesn't dampen the frisson experienced almost daily by trampers across the country, particularly at that inevitable point on the bridge where there is transitory transverse movement—always cause for white knuckles and mumbled profanity.